Process of producing purified asphalt from soap-containing asphaltic petroleum residuum



Sept. 3, 1935. H F. T T 2,013,619

PROCESS OF PRODUCING PURIFIED ASPHALT FROM SOAP CONTAINING ASPHALTICPETROLEUM RESIDUUM Filed Sept. 50, 1955 2 Sheets-Sheet l PRESSUREfi'EL/EF lv/ zwsss; A/ar y 674175 2 00 Sept. 3, 1935. ANGSTADT 2,013,619

. PROCESS OF PRODUCING PURIFIED ASPHALT FROM SOAP CONTAINING ASPHALTICPETROLEUM RESIDUUM Filed Sept. 30, 1955 2 Sheets-Sheet 2 EMULS/FY/NG currwa Arman E a.

Patented Sept. 3, 1935 UITE PROCESS OF PRODUCING PURIFIED AS- PHALT FROMSOAP-CONTAINING AS- PHALTEC PETROLEUM RESIDUUM of New Jersey ApplicationSeptember 30, 1933, Serial No. 691,630

11 Claims.

In the distillation of lubricating oils from crude oil in accordancewith Pew Patent 1,761,153, dated June 3, 1930, and in accordance withother processes wherein an addition of sodium hydroxide, or similarlyacting alkali, is made to a crude or to a topped crude, there isproduced an asphaltic residuum containing soaps of petroleum fattyacids.

The petroleum residuum produced by the process described in the Pewpatent above noted has the following physical characteristics, dependingon the type of crude processed and the amount of oil remainingundistilled in the bottoms:

Gravity at 60 F 8-15 A. P. I. Flash-Cleveland open cup 400 F.Fire-Cleveland open cup 600 F. Saybolt Vis. at 210 F NW-5000 Thisasphaltic residuum, due to the fact that it contains approximately '7 to14% petroleum acid soaps of high molecular weight, is not usable, as itcomes from the still, for many commercial purposes, nor is it madeusable by oxidizing it by the usual blowing with air or steam. Due tothe presence of these soaps, the residuum is miscible, when slightlyheated, in substantially all proportions with water, forming therewithan emulsion which remains stable on cooling. In my application, SerialNo. 493,242, filed November 3, 1930, which has matured into Patent1,931,880, Oct. 24, 1933, I describe a process for extracting thesesoaps from the asphaltic bottoms. The process described, however, is nota continuous one and is therefore not practical where large quantitiesof this asphaltic residuum must be treated in order to remove the soapcontent. 7

An object of the present invention is to continuously produce anon-emulsifying asphalt from a petroleum residuum containing soapsformed by distillation in the presence of an alkali.

Another object of the invention is to produce a petroleum fatty acidfrom crude soaps extracted from the asphaltic residuum.

Another object of the invention is to convert such purified petroleumacid into an emulsifying oil for use as a cutting oil, insecticide andfor many other purposes wherein a readily emulsifiable mineral oil isrequired.

Still another object of the invention is to provide an emulsifiab-leroad oil by proper combination of a substantially dehydratednon-emulsifying asphalt and a petroleum fatty acid soap.

These objects are attained in my improved process. The process is notdependent for its execution upon any particular apparatus, but the oneshown in the drawings, which I shall describe in detail, is particularlyadapted to an efficient execution of the process.

Figs. 1A and 1B are diagrammatic views showing different parts of theentire apparatus, Fig.

1A showing that part of the apparatus in which acid soaps are extractedfrom the petroleum residue, and Fig. 1B that part of the apparatus inwhich the crude acid soaps are pumped and treated to produce finishedproducts therefrom.

In the drawings, l designates a line for feeding the asphaltic residuumfrom the source of supply to heat exchangers w and b. c designates amixing chamber for thoroughly mixing the residuum fed through line Iwith water, fed through line 2, which has been previously heated inexchanger d, as will be hereinafter more fully described. 3 designates aline leading from the mixing chamber through heat exchanger e and backto one end of heat exchanger (1.. Heat exchanger a is connected at theother end through line 6 with a steam heater f and a pressure separatorg. The top of pressure separator g is connected by line 5 with anasphalt dehydrator h and at the bottom, through line 6, with heatexchanger e, which in turn, through line I, is connected to heatexchanger (1. Heat exchanger it also communicates through line 9 andbranches therefrom with storage tanks 8.

Each of tanks 8 communicates with line l leading to an agitator 7c of atype ordinarily used in oil treating. From the bottom of agitator ismaterial may be drawn off through line I I having branches l2 and 13therein, branch line 52 leading to any suitable drain connection, andbranch line !3 to a storage tank It. This storage tank M is connected byline l with a vacuum distillation unit p which may be of any suitabletype. From the vacuum still p a line 56 leads to a storage tank ll and aline 18 leads to a storage tank i9. Storage tank 59 communicates throughline 20 with an agitator m, the bottom of which communicates with astorage tank 2! through line 22.

Agitator 7c is provided with an inlet pipe 23 for feeding sulphuric orother suitable acid contained in tank 24 and with line 25 for feedingrefined mineral oil contained in tank 26. Agitator 7c is also providedwith an inlet 21 for water and is internally heated by means of a steamcoil 28. Steam coil 28 is, of course, provided with suitable inlet andoutlet pipes. In order to insure complete agitation, there is provided anozzle or rosette in the lower portion of the agitator connected with anair line 29.

Agitator m is provided with a heating coil 30 and air agitating meansfed by line 3 I. There are also provided lines 32 and s3 communicatingrespectively with tanks 34 and 35 for storing sodium hydroxide solutionand refined mineral oil, respectively to be fed to the agitator.

In operation, petroleum residuum is fed to the apparatus through line I.This asphaltic residuum, which is the bottoms from a process such asthat of the above mentioned Pew patent, is

usually at a temperature from 600 to 650 F., the temperature dependingon the type of crude or mixture of crudes which is being distilled andthe amount of lubricants removed therefrom. This residuum at thetemperature mentioned is much too hot for immediate admixture withwater,which is necessary to the present process, as such high temperatureswould necessitate maintaining the mixture under extremely high pressure.Therefore, the residuum is cooled to about 200 F., and mixed with waterat the same temperature, and at a pressure, but slightly aboveatmospheric, that will not effect the formation of steam. To effect aninitial cooling preparatory to admixing the residuum with water, it ispassed through heat exchanger a, wherein it is cooled to a temperatureapproximating 380 F. by passing in exchange with residuum which has beenalready mixed with water, and which is being heated for passage to theseparator. In order to cool the residuum still further before admixturewith water, it is passed through exchanger b, wherein it is cooled to200 F. by indirect heat exchange with water. After leaving the exchanger b the mixture is passed into the mixing chamber 0. Just prior toits passage into the mixing chamber, the residuum is mixed with waterentering through line 2, at substantially the same temperature. Thiswater, as shown in the drawings, is heated in heat exchanger (1 by heatexchange with crude soap solution which has been separated from theasphalt-water emulsion. Sufficient pressure is imposed on line 2 to atleast equal the pressure of the residuum passing into the mixer throughline I. Such pressure is imposed by the pump shown in the drawings.While in the mixer c the residuum and water are thoroughly mixed andform an emulsion which is stable at low temperature and atmosphericpressure. This emulsion is withdrawn through line 3 by means of the pumpshown and is passed through heat exchangers e and a, line 4 and heatexchanger 1 to the separator g. In passing through heat exchanger e themixture is heated to a temperature approximating 265 F. by heatinterchange with the separated soap solution passing from the bottom ofthe separator. In passing through heat exchanger 0, the mixture isfurther heated to a temperature of 340 F. by heat exchange with thefresh residuum passing to the apparatus from the lubricating oil still.Exchanger (or steam heater) 1 is provided to supply any additional heatwhich may be necessary. For instance, if a crude having no extremelyhigh boiling fraction is being distilled in the lubricating oil stills,the bottoms will not, of course, be so highly heated. In this case itmay be necessary to supply additional heat by means of heater 1. In sucha case, heat exchanger 13 may be eliminated, since heat exchanger a willbe effective to reduce the residuum to the temperature required formixing with water in mixer c.

In some cases it may be advisable to cool the residuum before it is fedto the apparatus and store it. In this case it would be necessary toheat the oil preparatory to admission to mixer c.

The separator g has a capacity equal to that of a three hour through-putof residuum and water, that is, if the water-residuum through-put is5,000 gallons per hour, the capacity of the separator 9 would be in theneighborhood of 15,000 gallons. This large capacity is necessary toprovide sufficient time for the soap solution to separate from theasphalt. As before explained, the emulsion of residuum and water isstable, at atmospheric pressure, up to the boiling point of water. Thisfact makes separation an extremely difficult operation. In order toeffect separation, the mixture is heated to about 350 F. and ismaintained under a pressure of 120 pounds per square inch or more. Thispressure is sufiicient to prevent vaporization of the water at thetemperature given, and is effective to cause a separation of the asphaltand soap solution when the mixture is maintained in a substantiallyquiescent state. Since the capacity of the separator g is equal to threeor more times the hourly throughput, the mixture must remain in theseparator for a period of time which is sufficient to cause a separationof the asphalt and soap solution. Since the asphalt has a specificgravity less than that of water, it rises to the top and the soapsolution settles to the bottom. The particular separator 9, shown in thedrawings, is also conducive to a thorough separation of soap and asphaltdue to its T-shape construction. In order to provide for the properefilux of the two constituents, there is provided a ball float 35connected by proper linkage with a valve 3? in the soap solution outflowline 5. The ball 3% and controlling linkage are so regulated that theball remains at the interfacial layer between the soap solution andseparated asphalt. This arrangement prevents a too rapid withdrawal ofeither the soap solution or asphalt.

The asphalt, which is almost water free, passes out through line 5 andenters the dehydrator h, line 5 being provided with a pressure reliefvalve for stepping down the pressure to a point which will permit theevaporation of any water contained in the asphalt. This water vapor ispassed out of the dehydrator through line 38 and the dehydrated asphaltis removed through line 39. Both lines 38 and 39 are provided withcontrol valves so that the pressure within the dehydrator it may beproperly regulated. The asphalt flowing out through line 39 is soap-freeand therefore non-emulsiflable and is in condition for blowing, etc., torender it usable as a road building material, roofing material, etc.,and when properly treated forms a high grade asphalt.

The soap solution flowing out through line 6 passes through heatexchanger e wherein it preheats the residuum-water mixture flowing tothe separator, and then flows through line 1 to heat exchanger (1'wherein it exchanges heat with cold water flowing to the mixer c, asalready described. The soap solution has a temperature of about 340 F.on leaving the separator, is cooled to about 250 F. in exchanger e andis further cooled to about 110 F. in exchanger d, whence it flows tostorage tanks 8.

While in the preferred practice of the process the flow of the mixtureinto the gravity separator g and the outflow separated asphalt andimpure soap solution therefrom are absolutely continuous, such inflowand outflow may be less desirably more or less intermittent. In claiminga substantially continuous inflow and outflow I do not mean tonecessarily exclude such interruptions of the flow as would not convertthe process into one in which the separation is a batch separation.There are certain more specific features of the process, howeverindependent of the provision for substantially continuous operationwhich afford advantages over the process of my prior application, suchas the separation of the purified asphalt and the impure soap solution.

When starting up the apparatus, a complete converted to acids.

separation of the mixture used primarily to fill the system will not beeffected and this mixture should therefore be recycled. This recyclingis effected by diverting soap solution, containing unseparated asphalt,from line l through branch line 40 to the mixer c. In this operation thevalve in line 5 is closed to prevent efflux of unseparated material fromthe top of the separator.

For some uses it is desired to provide an asphalt-soap mixturecontaining a predetermined proportion of soap. For this purpose line iis also connected, by means of valve-controlled branch line 4 l with anevaporator a. This evaporator serves to vaporize the water contained inthe soap solution. The vapor is passed off through line 42 anddehydrated soaps off through line 43 to line 29 where it mixes withsoapless asphalt from dehydrator h. The resultant product is, forexample, an emulsifiable road oil. The

I. asphaltic residuum as it comes from the lubricating oil stillscontains too much soap for use as a road oil and since it is impossibleto remove only a. small portion of the soap economically, and difficultto remove only a predetermined proportion, it is much more practicableto remove all of the soaps and then add a portion of the removed soapsto the dehydrated asphalt. This mixture of soap and asphalt may, ifdesired, be cut back with a mineral oil of the proper viscosity.

The soaps contained in solution in tank 8 are very impure, since theycontain asphaltic compounds which cannot be separated by any physicalprocess but require a chemical treatment. In order to purify thesesoaps, they should be first To convert the soaps contained in solutioninto acids and separate them from the large amount of water in whichthey are dissolved, they are passed through line it by means of the pumpcontained therein into the batch agitator It. To the soap solution inthe agitator it there is added the proper quantity of sulphuric or othersuitable acid to react with and precipitate any asphaltic products andto break down the soaps and convert them into the petroleum fatty acids.After the proper amount of acid has been added to the agitator, air isadmitted through line 29 to cause the agitation of the mixture and steammay be admited to coil 28 to maintain the materials at the desiredtemperature. When the reactions are complete, the

air supply for agitation is cut oif and the material within the agitatoris permitted to assume a quiescent state. This causes settlement of anysludge, formed by the reaction of the sulphuric acid on the asphalticmaterial, to the bottom of the agitator and also causes a formation oftwo liquid layers, a lower layer of water and an uper layer of petroleumacids. These acids are not fluid at normal temperature, and thereforeshould be kept heated by means of steam coil 28. After settling hastaken place, and the acid and water layers are distinct, the sludge andwater are drawn off through lines H and I2, leaving only the rawpetroleum acid within the agitator. If these acids are to be purifiedimmediately by vacuum distillation, they are immediately transferred tothe distilling apparatus without cooling. However, since this part ofthe process is a batch process it is usually not practicable to distillthem immediately. They are therefore admixed with a light oil, which maybe an animal, vegetable, or mineral oil, but which is preferably amineral oil, for instance one having a viscosity of 100 at 100 F., insuch amount as to assure their being fluid at normal temperature. Suchoil' may be supplied from tank 26 through line 25. After such additionof light oil is made, the petroleum acid and oil mixture is transferredto storage tank M through lines II and I3.

When a sufficient quantity of raw petroleum 1 acids have been collectedin tank I4, they are removed through line I5 by means of pump shown, tothe vacuum distillation unit 11. The bottoms from this vacuumdistillation are removed through line l6 to storage tank I1, and areused for fuel oil, etc. The finished acids are removed from the vacuumdistillation process through line l8 to tank I9.

These acids, which may be fractionally condensed in any number of cuts,vary from light straw color in the lightest cuts to dark red in theheaviest cuts. The saponification values of the cuts also vary so thatthe various cuts may be blended as desired to form a product ofpredetermined color and saponification number.

When it is desired to make up a batch of cutting oil, insecticide, orany other material for which the use of these petroleum acids ispracticable, they are removed through line 20 to agitator m. They aretherein heated by means of the steam coil 30 and have added thereto afurther quantity of light mineral or vegetable oil of, say, 100viscosity at 100 F. When the oil and petroleum acid are completely mixedand heated, sodium hydroxide solution is admitted, through line 32, fromtank 34. This addition of sodium hydroxide causes a re-saponification ofthe petroleum acids in admixture with the light oil. After thesaponification reaction is complete, the mixture is heated in order tovaporize water added with the sodium hydroxide and to vaporize any waterformed by the saponification reaction. After all water has beenvaporized, the soap and oil mixture is removed through line 22 tostorage tank 2 i. This mixture is miscible with watersubstantially inall proportions at any temperature.

The pure petroleum acids which are obtained after settling the sludgeproducts and water in agitator k belong to several series of organicacids. Of the acids of the series having the general formula, CnH2n602,there are three represented which have the formula:

Of the acids having the general formula CnH2n802,

there are three which have the formula:

Of the acids having the general formula CnH2nl0O2,

there are two represented which have the formula The molecular weightsof these acids run from 259.5 to 372.

By way of a specific example, there is given below a resume of theprocess giving various figures for the input of materials and theresultant products obtained, based on an hourly throughput. There arecharged to the apparatus shown in Fig. 1, 3500 gallons per hour of anasphaltic residuum remaining after the distillation of lubricating oiland lighter fractions from crude oil. To these 3500 gallons per hourthere is added water to the amount of 5250 gallons and the two arethoroughly combined in the mixer c, forming an emulsion of 8750 gallons.On separation of the asphalt and soap solution there is obtained 3010gallons of substantially dehydrated soapfree asphalt, and 5740 gallonsof impure soap solution.

Agitator k is charged with 5740 gallons of soap solution containing 490gallons of impure soaps. To this solution is added per barrel ofsolution, 4.67 pounds of 66 B. (98%) sulphuric acid, which is justsufiicient to break down the soaps and make the solution slightly acid.After the sludge and water, amounting to about 5250 gallons, havesettled from the soap layer and have been drawn off, there are added tothe remaining acids, amounting to about 490 gallons, 245 gallons of alight oil having a viscosity of 100 at 100 F. After thorough mixture ofoil and acids has been efiected, the mixture is drawn off to storage.The vacuum distillation unit p is then charged with 735 gallons of theoil-petroleum acid mixture. This mixture has a saponification Value ofabout 35 mg. KOH. After vacuum distillation to purify the petroleumacid, it will be found that about 367 gallons of the original stockremain as bottoms and about 367 gallons have been taken over as finishedpetroleum acids and oil. This finished mixture has a saponificationvalue of 30-40 mg. KOH.

Agitator m is then charged with 367 gallons of the mixture of finishedpetroleum acid and light mineral oil, which is sapom'fied by theaddition of 26 gallons of 30% NaOH (Baum gravity 360). Aftersaponification has been completed, there is added 300 gallons of lightmineral or vegetable oil having a viscosity of 100 at 100 F. Aftercomplete admixture, the finished soap-oil solution is drawn off tostorage.

What I claim and desire to protect by Letters Patent is:

1. The process of producing, from soap-containing asphaltic petroleumresiduum, purified asphalt and purified organic acids, which comprisesflowing said residuum and water toward a common locus and mixing thesame, imposing a superatmospheric pressure thereon, substantiallycontinuously flowing the resultant mixture to a container of suificientcapacity to allow gravity settlement and therein maintaining the mixtureat an elevated temperature but under a superatmospheric pressuresufficiently high to prevent boiling with resultant re-entry of theseparated constituents into the emulsion or solution stage, separatelysubstantially continuously outflowing the separated soap-free asphaltand the impure soap solution, agitating the impure soap solution with amineral acid and separating water and acid sludge from the organic acidsthereby formed, and separating said organic acids from impuritiesassociated therewith.

2. The process of producing, from soap-containing asphaltic petroleumresiduum, purified asphalt and purified organic acid soaps, whichcomprises flowing said residuum and water toward a common locus andmixing the same, imposing a superatmospheric pressure thereon,substantially continuously flowing the resultant mixture to a containerof sufiicient capacity to allow gravity settlement and thereinmaintaining the mixture at an elevated temperature but under asuperatmospheric pressure sufficiently high to prevent boiling withresultant re-entry of the separated constituents into the emulsion orsolution stage, separately substantially continuously outflowing theseparated soap-free asphalt and the impure soap solution, agitating theimpure soap solution with a mineral acid and separating water and acidsludge from the organic acids thereby formed, separating said organicacids from impurities associated therewith, and re-saponifying thepurified organic acids.

3. The process of producing, from soap-containing asphaltic petroleumresiduum, purified asphalt and purified organic acids, which comprisesfiowing said residuum and water toward a common locus and mixing thesame, imposing a superatmospheric pressure thereon, substantiallycontinuously flowing the resultant mixture to a container of suflicientcapacity to allow gravity settlement and therein maintaining the mixtureat an elevated temperature but under a superatmospheric pressuresuificiently high to prevent boiling with resultant re-entry of theseparated constituents into the emulsion or solution stage, separatelysubstantially continuously outflowing the separated soap-free asphaltand the impure soap solution, converting the soaps of the impure soapsolution to organic acids by agitation with a mineral acid, adding oiland separating water and sludge from the organic acids and oil, anddistilling off the organic acids and oil from the impurities associatedtherewith.

4. The process of producing, from soap-containing asphaltic petroleumresiduum, purified asphalt and purified organic acids, which comprisesflowing said residuum and water toward a common locus and mixing thesame, imposing a superatmospheric pressure thereon, flowing theresultant mixture to a separate locus and there, at a substantiallyhigher temperature while maintaining the pressure suificiently high toprevent boiling with resultant destruction of the soaps or the re-entryof the separated constituents into the emulsion or solution stage,effecting gravity settlement, separately outflowing the separatedsoap-free asphalt and the impure soap solution, agitating the impuresoap solution with a mineral acid and separating water and acid sludgefrom the organic acids thereby formed, and separating said organic acidsfrom impurities associated therewith.

5. The process of producing, from soap-containing asphaltic petroleumresiduum, purified asphalt and purified organic acid soaps, whichcomprises flowing said residuum and water toward a common locus andmixing the same, imposing a superatmospheric pressure thereon, flowingthe resultant mixture to a separate locus and there, at a substantiallyhigher temperature while maintaining the pressure sufiiciently high toprevent boiling with resultant destruction of the soaps or the re-entryof the separated constituents into the emulsion or solution stage,eiTecting gravity settlement, separately outflowing the separatedsoap-free asphalt and the impure soap solution, agitating the impuresoap solution with a mineral acid and separating water and acid sludgefrom the organic acids thereby formed, separating said organic acidsfrom impurities associated therewith, and re-saponifying the purifiedorganic acids.

6. The process of producing, from soap-com taining asphaltic petroleumresiduum, purified asphalt and purified organic acids, which comprisesfiowing said residuum and water toward a common locus and mixing thesame, imposing a superatmospheric pressure thereon, flowing theresultant mixture to a separate locus and there, at a substantiallyhigher temperature while maintaining the pressure suiiiciently high toprevent boiling with resultant destruction of the soaps or the re-entryof the separated constituents into the emulsion or solution stage,effecting gravity settlement, separately outflowing the separatedsoap-free asphalt and the impure soap solution, converting the soaps ofthe impure soap solution to organic acids by agitation with a mineralacid, adding oil and separating water and sludge from the organic acidsand oil, and distilling off the organic acids and oil from theimpurities associated therewith.

7. The process of producing purified asphalt from soap-containingalphaltic petroleum residuum which comprises flowing said residuum andwater toward a common locus and. mixing the same, imposing asuperatmospheric pressure thereon, substantially continuously flowingthe resultant mixture to a container of suflicient capacity to allowgravity settlement and therein maintaining the mixture at an elevatedtemperature but under a superatmospheric pressure sufiiciently high toprevent boiling with resultant reentry of the separated constituentsinto the emulsion or solution stage, separately substantiallycontinuously outflowing the separated soapfree asphalt and the impuresoap solution, dehydrating outflowing soap solution and flowingdehydrated soaps to the outflowing soapless asphalt in predeterminedproportions to form an emulsifiable oil containing a predeterminedproportion of soap less than that contained in the original asphalticpetroleum residuum.

8. The process of producing purified asphalt from soap-containingasphaltic petroleum residuum which comprises flowing said residuum andwater toward a common locus and mixing the same, imposing asuperatmospheric pressure thereon, flowing the resultant mixture to aseparate locus and there, at a substantially higher temperature whilemaintaining the pressure suificiently high to prevent boiling withresultant destruction of the soaps or the re-entry of the separatedconstituents into the emulsion or solution stage, effecting gravitysettlement, separately outflowing the separated soap-free asphalt andthe impure soap solution, dehydrating separated soap solution and addingthe dehydrated soaps to the soapless asphalt to form an emulsifiable oilcontaining a predetermined proportion of soap less than that containedin the original asphaltic residuum.

9. The process of producing, from soap-containing asphaltic petroleumresiduum, an emulsifiable road oil and purified organic acids, whichcomprises flowing said residuum and water toward a common locus andmixing the same, imposing a superatmospheric pressure thereon,substantially continuously flowing the resultant mixture to a containerof sufiicient capacity to allow gravity settlement and thereinmaintaining the mixture at an elevated temperature but under asuperatmospheric pressure sufficiently high to prevent boiling withresultant re-entry of the separated constituents into the emulsion orsolution stage, separately substantially continuously outflowing theseparated soap-free asphalt and the impure soap solution, dividing theoutflowing soap solution into two streams, dehydrating the soap solutionof one stream and mixing it with outfiown soapless asphalt, agitatingthe soap solution of the other stream with a mineral acid and separatingwater and sludge from the organic acids thereby formed and separatingsaid organic acids from impurities associated therewith.

10. The process of producing purified asphalt from soap-containingasphaltic petroleum residuum which comprises flowing said residuum andwater toward a common locus and mixing the same at a relatively lowtemperature and at a relatively low superatmospheric pressure suflicientto prevent boiling at such temperature, flowing the resultant mixture toa separate locus and there, at a temperature and pressure substantiallyhigher than the temperature of mixing and at a pressure sufficientlyhigher than the temperature of mixing to prevent boiling with resultantdestruction of the soaps or the reentry of the separated constituentsinto the emulsion or solution stage, effecting gravity settlement,separately outflowing the separated soapfree asphalt and the impure soapsolution, reducing the pressure on the asphalt to effect itsdehydration, and without reduction of pressure cooling the outflowingstream of the impure soap solution.

11. The process of producing purified asphalt from soap-containingpetroleum residuum which comprises flowing said residuum and watertoward a common locus and there mixing the same at a relatively lowtemperature under a pressure sufliciently high to prevent boiling,substantially continuously flowing the resultant mixture to a containerof sufficient capacity to allow gravity settlement and in the course ofthe flow of said materials heating the same to a temperaturesufficiently higher than the temperature of mixing to throw the soapsout of solution or emulsion with the asphalt impurities associatedtherewith but not high enough to effect boiling at the existing pressureand consequent destruction of soaps, continuing to maintain the mixturein the container at a temperature not substantially below thetemperature to which it has been heated while continuing to maintain itunder a boiling temperature at the existing pressure, allowing gravitysettlement in the container, separately substantially continuouslyoutflowing therefrom the separated soapfree asphalt and the impure soapsolution, reducing the pressure on the asphalt to effect its dehydrationand without reduction of pressure cooling the impure soap solution.

HARRY F. ANGSTADT.

